The Clinical Therapeutic Effect Of Herbst Fixed Function Appliance Therapy Method In The Patients With Late Growth And Development Osseous Ⅱ Class

Objective: to study the clinical therapeutic effect of Herbst fixed function appliance and fixed appliance therapy method in the patients with late growth and development osseousⅡclass.Materials and methods: a case of patient with late growth angle’s ClassⅡ mandibular retraction was selected as the research object.The female patient was 15 and had permanent teeth jaw.The model and the measurement analysis of head side piece showed the molar relation was far-middle tip to tip,with quite deep coverage.Upper anterior teeth long axis incisor was flared,and the down front teeth long axis was vertical.Maxillary crowding degree was 1.5mm and underjaw crowding degree was 3mm.It showed convex shape and was at the CVS5~CVS6 stage.Because the patient was in the late growth had still had growth potential,the author finally chose the growth modified face type to decide whether to combine with the therapeutic schedule of fixed correctional tooth extraction.First of all,the author chose Herbst fixed function appliance to conduct growth improvement for 6 months so as to make the molar relationship close to near middle and make incisor edge close to the reverse jaw.After the improving the face type through growth improvement,fixed appliance was carried out;the teeth recycling clearance was leveled;Ⅱ class traction was used to keep the new position of mandible and play function.The face changed from convex to vertical type at this time.Results: the growth improved time and total expected treatment time are 6 months and 13 months respectively.After the treatment,it reached the neutral partial relation,with normal coverage;the side face was obviously improved.The comparison of the Before and after the contrast function correction shows:(1)In view of the upper and lower jaw bone,bone growth and position change is smaller,it mainly is the change of alveolar process;it is associated with later correction timing and the patient has limited growth and development potential.(2)The molar relation changes and the coverage of anterior teeth decreases mainly because the change of the tooth position and remodeling of alveolar process tissue.(3)the tongue incline motion of incisor long axis makes upper lip tissue relatively move backward;the lip motion incline motion of anterior teeth long axis,the mandibular growth and reconstruction of alveolar change the patient’s face shape(from convex shape to vertical shape),avoiding tooth extraction to change face shape and providing a better choice for the orthognathic surgery borderline cases.(4)The increase of dental arch width shows that the appliance can be used for the maxillary expansion of the patients with dental arch stenosis or mild crowded dentition,but the long-term effect and stability after the maxillary expansion remain to be confirmed through the accumulation of a large number of clinical cases and long-term follow-up observation of the patient.(5)Because the patient’s treatment timing is late stage of growth and development,the function correction can only stimulate her less growth potential and she needs to strengthen the curative effect of mandibular antedisplacement by cooperating with jaw tractionⅡclass after the demolition of function appliance.Conclusions: by improving the growth of the patient with late angle’sⅡ class through Herbst fixed function appliance,the patient’s upper and lower molar teeth and canine teeth restore neutral relation;the coverage becomes normal;the facial soft tissue,especially the side face is greatly improved.However,there is still certain compensatory labial inclination on the incised teeth,showing Herbst fixed function appliance slightly changes the bone of patient at later stage of growth but greatly changes teeth.Therefore,the best timing for patients with angle’s class II malocclusion is before the growth peak or growth peak and it is better to achieve early detection and early treatment.